Paul Beament, 45, of Acton, West London, was jailed for four years, four months and Dean Conyers of Kilburn, London, for two years for conspiracy to supply cannabis.

Peter Dolan, 33, from Bootle, Liverpool, was jailed for 18 months for supplying cannabis and possessing cocaine. They had all admitted the offences at a previous hearing.

An investigation by the National Crime Agency found the gang employed a number of tactics in an attempt to avoid detection.

They communicated via a number of mobile phones and used public phone boxes for particularly sensitive conversations.

Adopting codewords, such as “scratch” for cash, “pollen” for cannabis and “sweat” for Scottish bank notes, they also used the serial numbers on banknotes as “passcodes” to validate their couriers’ identities and ensure cash was handed over to the right person.

The holder of a cash haul would be given the serial number on a £5 note via a text message.

The collecting criminal would be in possession of the actual £5 note displaying that number.

In some cases the criminal cash was credited to Euro top-up cards and spent abroad, including in Holland and Spain where Budgen and his wife spent a considerable amount of time.

Simon Flowers Branch Commander NCA Wales, said: “This was a professionally managed crime group who used a range of tactics to try and avoid law enforcement. But as today’s sentence shows we were able to follow their criminal activity across Europe and bring them to justice.

“Budgen was well established within the international criminal community, and had built up a wide network of criminal associates throughout the UK and Europe.

“He was clearly the controller of this group, not only overseeing the supply of cannabis and hiding criminal proceeds, but connecting criminals across Europe to professional money launderers.”

The case began in 2010 when investigations revealed the full extent of Budgen’s criminal connections.

It led to numerous separate operations being launched across Europe and the arrest of over 50 people for a range of crimes including drug trafficking and money laundering.

Cash seizures have so far totalled more than £1m alongside substantial criminal assets, several thousand kilos of cannabis and multiple kilos of cocaine, amphetamine and methedrone.

Budgen and Beament were also given Serious Crime Prevention Orders, restricting their use of travel and communications for five years after they are released including mobile phones, internet access and use of public telephone boxes.